P0116

P0116-ENGINE COOLANT TEMPERATURE SENSOR CIRCUIT PERFORMANCE

For a complete wiring diagram, refer to the Wiring Information.





Theory of Operation

The Coolant Temperature Sensor is a variable resistor that functions as a normal two wire 5-volt sensor. The PCM supplies a 5-volt reference and a ground to the sensors low reference signal circuit.

- When Monitored:
Engine off time is greater than 480 minutes and the vehicle has been driven for one minute over 35 mph. Ambient temperature is greater than -64°C (-83°F).

- Set Condition:
Once the vehicle is soaked for a calibrated engine off time and then driven over calibrated speed and load conditions for some calibrated time, the PCM compares the Ambient, Engine Coolant and Intake Air Temperature Sensor values. If Ambient Air and Intake Air Temperature Sensors agree with each other but Engine Coolant Temperature does not agree with them, the Engine Coolant Temperature Sensor is declared as irrational. One Trip Fault. If the vehicle is equipped with the stop/start feature, the system will be disabled when this DTC is active.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

Diagnostic Test

1. ENGINE COOLANT TEMPERATURE
1. Turn the ignition off.
2. Allow the vehicle to sit with the ignition off for more than 480 minutes in an environment where the temperature is consistent and above -64°C (-83°F) or until the engine coolant temperature is equal to ambient temperature.
3. Turn the ignition on.
4. With the scan tool, compare the AAT, ECT and IAT sensor values.

Is the Engine Coolant Temperature Sensor value within 15°C (59°F) of the other two sensor values?

Yes

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.

No

- Go To 2

2. CHECK FOR EXCESSIVE RESISTANCE IN THE (K2) ECT SIGNAL CIRCUIT




1. Turn the ignition off.
2. Disconnect the Engine Coolant Temperature Sensor harness connector.
3. Disconnect the PCM C2 harness connector.
4. Measure the resistance of the (K2) ECT Signal circuit between the Engine Coolant Temperature Sensor harness connector and the PCM C2 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 3

No

- Repair the (K2) ECT Signal circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

3. CHECK FOR EXCESSIVE RESISTANCE IN THE (K915) SENSOR GROUND CIRCUIT




1. Measure the resistance of the (K915) Sensor Ground circuit between the Engine Coolant Temperature Sensor harness connector and the PCM C2 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 4

No

- Repair the (K915) Sensor ground circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

4. ECT SENSOR VOLTAGE
1. Turn the ignition off.
2. Reconnect the PCM C2 harness connector.
3. Turn the ignition on.
4. With the scan tool, read the Engine Coolant Temperature Sensor voltage.

NOTE: The sensor voltage should be approximately 5.0 volts (plus or minus 0.1 volts) with the connector disconnected.

5. Connect a jumper between the (K2) ECT Signal circuit and the (K915) Sensor Ground circuit AT the Engine Coolant Temperature Sensor harness connector.

NOTE: The sensor voltage should be approximately 0.0 volts (plus or minus 0.1 volts) with the jumper in place.

Does the scan tool display the voltage as described above?

Yes

- Replace the ECT Sensor. Engine Coolant Temperature Sensor - Removal.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 5

5. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the ECT Sensor and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the ECT Sensor and Powertrain Control Module connectors.
4. Perform any Technical Service Bulletins that may apply.

Were there any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Replace and program the Powertrain Control Module. Powertrain Control Module - Removal.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.